Log entries for automatic global group membership changes are created on local wikis, not Meta. For example: https://en.wikibooks.org/wiki/Special:Log/gblrights (taken from T397224#11376026).
Is this expected? Until now I thought that all global group membership changes should happen on Meta. On the other hand, https://en.wikipedia.org/wiki/Special:Log/gblrights also has some real global group membership changes from 2014 and earlier. Is this something we changed at some point (maybe T19308?), or is it still okay?